Electric lamp



Oct. 19, 1937. LE ROY H.IBAKER. 2,096,603

ELECTRIC LAMP Filed Jan. 26, 1937 amen TM LeRog H ..B afier,

Patented @ct. 1, N37

i. eras ELECTRIC LAMP Le Roy H. Baker, Corning, N. Y., assignor of onethird to Joseph F. Eberle, Westfield, Pa.

Application January 26, 1937, Serial No. 122,474

4 Claims.

This invention relates to the art of electric lamps, and more particularly to multiple filament electric lamps.

Many attempts have been made to produce a successful multiple filament electric lamp, but these have generally been lacking either in practicality or in the assurance of continued satisfactory functioning.

I have discovered that a highly useful multiple filament electric lamp can be made by the use of a third filament having a fixed and a floating connection with the junction points of the other filaments in the manner more fully pointed out hereinafter.

It is therefore an object of this invention to provide a new and useful multiple filament electric lamp.

It is another object of my invention to provide an electric lamp which will be automatically restored to its original brilliancy upon the burning out of one of the filaments.

It is also an object of this invention to provide an electric lamp in which, after one of the original filaments burns out and the lamp has been restored to full efllciency, the lamp can be restored to one-half efiiciency after a second filament burns out.

With the above and other objects in view, which will be apparent as the description proceeds, I have set forth my invention in the following speci- .fication and have illustrated it in the accom panying drawing, in which:

Figure 1 is a perspective view of my improved lamp;

Fig. 2 is a horizontal section, on an enlarged scale on the line 22 of Fig. 1, showing the relation of the filaments; and

Fig. 3 is a transverse vertical section, also on an enlarged scale, on the line 3-3 of Fig. 1.

Referring to the accompanying drawing, l designates a preferred embodiment of my new, improved electric lamp, which comprises a suitable metal base a glass globe l2, a. lead-in wire support l3 which is preferably made of glass, and with the lead-in wires l4 and I5 that are connected at l6 and II, respectively, as by any suitable sealing means, with the adjacent ends of a pair of filaments 20 and 2|.

As shown, the filaments 20 and 2| are preferably of generally semi-circular shape, but at the points at which these filaments are united by the seal IE to lead-in wire l4 they are provided with angular portions 22 and 23, respectively, with an intermediate space 24 therebetween.

I also provide a third filament 25, which is also preferably semi-circulan that is connected at IT to the junction points of one end of filaments 20 I and 2| with lead-in wire l5, and which at its When either filament 2| or.2ll burns out, the

unequal heatthus createdin the remaining filament will defiect the wing member 26 into contact with the surviving filament 21L or 2| to which it will become welded by the resultant heat.

The lamp will then be restored to its original 5 brilliancy.

Upon the subsequent burning out of either filament 25 or the surviving filament or 2|,

from the first burning out, my lamp will then continue to give one-half of the original brilliancy of the lamp.

2C In practice I prefer to make the filaments 20,

2| and of tungsten or any other suitable filament material, and of equal resistance. It will be understood, however, that they may take any desired form and that they may be made of un- 25 equal light-giving power when desired. For example, filament 25 may be of a greater or less resistance than filament 20 or 2|. Where the voltage is likely to vary, an extra measure of safety can be obtained by having filament 25 30 made to carry a higher voltage than the other filaments.

The wing member 26 is made of any suitable thermostatic materials, such as, Monel metal,

Swedish iron, or any alloy which heat will easily distort, and may be made of any desired shape if found advisable for efliciency or any other reason, but is preferably made as a fiat strip as indicated in the drawing.

Although I have used the expression "burns out to indicate the cause of the failure of one or more of the filaments of my improved lamp, it will be understood that any other cause of failure of one or more of these filaments, as by mechanical breakage, or the failure of one of the cement seals H5 or II, will result in a similar operation,

. with respect to filament 25 and its wing member It will, therefore, be' apparent that my new lamp, which may be made in any desired shape or candle power, comprises a. pair of filaments which are normally lighted when the lamp is in use and with a third filament which is adapted to restore the lamp to its original brilliancy upon the failure of one of the first-mentioned filaments,

that normally occupies the 5 and which is also adapted upon the failure of a second filament to be able to function at one-half of the original brilliancy.

As manyapparently widely different embodiments of this invention may be made without departing from the spirit thereof, it is understood that I do not limit myself to the foregoing embodiments or description except as indicated in the following patentclaims:

I claim:

1. An electric lamp comprising a pair of lead-in wires, a pair of filaments connected in multiple to the lead-in wires, a third filament permanently connected to one of the lead-in wires, and with its opposite end positioned adjacent the other leadin wire but in proximity to and between the points at which the two first mentioned filaments are connected to the second lead-in wire, said third filament being normally disconnected from the second lead-in wire but being adapted to be deflected into permanent engagement therewith upon the breaking of either of the first mentioned filaments.

2. An electric lamp comprising a pair of filaments connected in multiple for the normal operation of the lamp, :3. third filament permanently connected to one junction point of the two first mentioned filaments and with its opposite end arranged adjacent to but out of contact with the junction point of the other ends of the two first mentioned filaments, said third filament being adapted to be deflected into engagement therewith by the resulting heat in the event that one of said first mentioned filaments burns out or breaks, thereby causing said third filament to become firmly welded to said second junction point of said first mentioned filaments to restore the lamp to its original candle power.

3. An electric lamp comprising double filaments of equal brightness for its normal operation, and a third filament which has one end permanently connected to both of the first mentioned filaments and its opposite end arranged adjacent to but normally out of contact with both of the first mentioned filaments, said third filament being automatically lighted in the event one of said first mentioned filaments fails, to thus restore the lamp to its original brilliancy, said lamp functioning at one-half of its original brilliancy upon the failure of the second of the normal filaments or the third filament.

4. An electric lamp comprising a base, two lead in wires extending therethrough, a pair of filaments each arranged in a semi-circle with the ends of the semi-circles adjacent to one another and united at those points to the lead-in wires,-and a recess at one of said junction points formed by an offset in the filaments adjacent one of the lead-in wires to receive the free end of a thermostatically controlled third filament which is normally disconnected therewith but whose opposite end is permanently connected to the other common junction point of the first mentioned filaments with the other lead-in wire.

LE ROY H. BAKER. 

